diff options
Diffstat (limited to 'drivers/usb/phy/phy-am335x-control.c')
| -rw-r--r-- | drivers/usb/phy/phy-am335x-control.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/usb/phy/phy-am335x-control.c b/drivers/usb/phy/phy-am335x-control.c index d75196ad5f2..35b6083b799 100644 --- a/drivers/usb/phy/phy-am335x-control.c +++ b/drivers/usb/phy/phy-am335x-control.c @@ -3,6 +3,7 @@ #include <linux/err.h> #include <linux/of.h> #include <linux/io.h> +#include <linux/delay.h> #include "am35x-phy-control.h" struct am335x_control_usb { @@ -86,6 +87,14 @@ static void am335x_phy_power(struct phy_control *phy_ctrl, u32 id, bool on) } writel(val, usb_ctrl->phy_reg + reg); + + /* + * Give the PHY ~1ms to complete the power up operation. + * Tests have shown unstable behaviour if other USB PHY related + * registers are written too shortly after such a transition. + */ + if (on) + mdelay(1); } static const struct phy_control ctrl_am335x = { |